激光清洗铝合金表面漆层的粗糙程度变化检测与分析

Detection and analysis of roughness variation of laser cleaning to remove paint layer on Aluminum alloy

采用1064 nm脉冲激光清洗2024铝合金表面氟碳漆层时,表面粗糙度的变化引起漆层对激光吸收作用的改变,易使得热量吸收过度造成基材损伤.为此,针对激光清洗过程中漆层表面粗糙形貌的检测与分析,设计了脉冲激光清洗实验系统,分析了2种激光清洗模式下氟碳漆层表面粗糙形貌的产生机制,并采用激光共聚焦显微镜对表面粗糙度进行了测试与表征,研究了激光逐层去除氟碳漆层时表面粗糙度的演化行为.结果表明:1)在激光清洗过程中,激光烧蚀和振动作用后漆层均会产生粗糙表面;2)激光逐层清洗过程中,表面粗糙度随着激光作用次数的增加呈非线性增大,当激光作用14次后漆层表面粗糙度已经达到35.88μm,相比于激光第1次作用后增加了370%;3)激光逐层除漆过程中粗糙表面对激光吸收率具有增加作用,在激光7次作用后漆层粗糙表面对激光的吸收率增加了32.8%.

When 1064 nm laser was used to clean 2024 aluminum alloy skin surface fluorocarbon paint layer,the change of surface roughness caused the alteration of absorption effect of paint layer on laser,which easily causes excessive absorption of heat to produce substrate damage.Therefore,for the detection and analysis of surface roughness in the laser cleaning process,the pulsed laser cleaning experimental system was designed.The generation mechanism of surface roughness morphology of fluorocarbon paint layer was analyzed under two laser cleaning modes,and the surface roughness was tested and characterized by laser scanning confocal microscope.The evolution of surface roughness was studied when the fluorocarbon paint layer was removed by laser.The result showed that:1)The laser ablation mechanism and vibration mechanism will produce rough surface in the laser cleaning process;2)With the increase in the times of laser cleaning,the surface roughness presents the nonlinear increase in the laser layer-by-layer cleaning process.After the laser cleaning 14 times,the roughness of the paint layer has reached 35.88μm,which is an increase of 370%compared to that of the first cleaning.3)The presence of rough surface has a significant increase effect on the laser absorption rate in the process of laser layer by layer paint removal.After the laser cleaning 7 times,the absorption rate of the rough surface of the paint layer on laser increase by 32.8%.